Switches



Feb. 5, 1963 w. G. BURT, JR 3,076,883

SWITCHES Filed Jan. 13, 1961 5 Sheets-Sheet 1 Feb. 5, 1963 W. G. BURT, JR

SWITCHES 5 Sheets-Sheet 2 Filed Jan. 15, 1961 Feb. 5, 1963 w. e. BURT, JR 3,076,883

SWITCHES Filed Jan. 15, 1961 3 Sheets-Sheet 3 United States Patent 3,ti76,8ti3 SWETCHES William G. Burt, in, Weston, Mass, assignor to Generfl Qommunieation Qompany, Boston, Mass, a corporation of Massachusetts Filed .lan. 13, 1961, Ser. No. 82,618 6 Claims. (ill. Mill-153) The present invention relates to improvements in a coaxial or other waveguide switch and more particularly to a switch assembly of the general type of which the stator comprises a fiat connector assembly plate having a plurality of waveguide connectors terminating in flat, endon relation, and of which the movable member cooperating therewith includes a bridging conductor arranged to close a waveguide circuit between a selected two of said connectors.

In a coaxial or other waveguide switch of the type described it is of particular importance to secure continuous peripheral contact of the outer conductor as between the movable member and the stator in order to reduce to the greatest possible degree the inevitable leakage of the radio frequency signal from the active to an inactive conductor. Heretofore, however, this has only been achieved through precision machine work, which is so expensive as to render the achievement of low leakage in such structures impractical in most instances. Too, particular problems are present with coaxial switches, due to the presence of a conductor within the surrounding waveguide.

It is hence an object of the present invention to provide an improved switch of this general description which is of simple construction yet which will at the same time operate with the high degree of accuracy and precision required without the necessity of impractical machine work.

In accordance with this object, a major object of the invention consists in the manner of supporting and guiding the movable switch member to cause the bridging outer conductor to establish a continuous peripheral contact with any two selected connectors, in such a manner that cross-talk causing radio frequency leakage is much reduced.

Another object of the invention is to control the contacting movement of the central conductor of a coaxial switch in such a manner as not to interfere with the function of the surrounding conductor, as well as to prevent damage to the central conductor during switching.

In order to accomplish these objects of the invention, the movable switch member is supported so as to provide a universal connection freely adjustable to permit the two ends or" the surrounding tubular waveguide conductor of the bridging conductor assembly to be brought and maintained in continuous peripheral Contact with the associated connectors. An inner conductor may preferably be pressed against its mating inner conductor by independent means so as not to detract from the forces applied between outer conductors.

With the above and other objects in view as may here inafter appear the several features of the invention consist also in the preferred devices, combinations, and arrangement of parts hereinafter described and claimed which, together with the advantages to be obtained thereby, will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a sectional view of a switch embodying features of this invention;

FIG. 2 is a bottom view of the switch;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1 showing the switch in a contacting position;

li atenteti Feb. 5, 1%5

FIG. 4 is a sectional view taken along line 44 of FIG. 1 showing the switch as in FIG. 3;

FIG. 5 is a sectional view similar to FIG. 4, but showing the switch in an out-of-contact position;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 5;

FIGS. 7 to 10 inclusive illustrate a modified form of switch mechanism of my invention;

FIG. 7 being a sectional view in side elevation of the modified switch structure;

FIG. 8 being a sectional bottom plan view taken on a line 3-8 of FIG. 7;

FIG. 9 being a detail sectional view in side elevation taken on a line 9-9 of FIG. 8; and

FIG. 10 being a detail sectional end view taken on a line lit-16 of FIG. 9; and

FIGS. 11 to 13 inclusive illustrate a further modified form of switch embodying the invention;

FIG. 11 being a view in side elevation of the modified switch structure in which two bridging conductors are shown for connecting selected peripherally arranged switch contacts;

FIG. 12 is a sectional view in side elevation taken on a line ll2ll2 of FIG. 11; and

FIG. 13 is a sectional bottom plan view taken on a line l3-l3 of PEG. 11.

The switch structure is best shown in FIGS. 1 and 2 in which the casing is comprised of motor housing 10, switch housing 12, and connector assembly plate 14. These casing elements are preferably made of metal. The connector assembly plate is equipped with a number of connector elements extending parallel to the axis of the switch and to each other. In the embodiment of the drawings shown, the coaxial conductors have a central and a surrounding tubular conductor terminating in fiat, end-on relation. More specifically, these surrounding conductors are defined by bores 15, 17, 19, 21, 2:3, 25 and 27 in said plate wherein one central connector element 16 is provided having six connector elements, 18, 2t), 22, 24, 26 and 28, arranged concentrically around it. These parts are all stationary.

The switching operation is performed by a rotor, the body of which is indicated at 38. The rotor body is made of metal, and in the embodiment shown is generally rectangular in shape, with a length sufficiently shorter than the inside diameter of switch housing 12 so that the rotor is free to move within the limitations of its mounting, which will be described later, without being constrained in its movement by the walls of the housing.

In this type of switch, advantage is taken of available methods by which close and precise mating or butting surfaces can be generated by practical machining methods, such as (without restriction thereto) the grinding of mating surfaces each to a high degree of flatness. When said connector plate 14 and the bottom surface of said rotor 36 are so mated the leakage of radio frequency signal from the rotor channel (due to discontinuity in the coaxial outer conductor at the point of mating) can be substantially eliminated, thus providing a high degree of attenuation, or cross-talk reduction between active and inactive radio frequency channels.

Extending transversely through rotor body 3% is a Waveguide defining cavity 31 having within it a bridging conductor 32, bent twice at right angles at intermediate points in its length and movably supported in said cavity by insulating blocks 34. One of the terminal ends of the bridging conductor is exposed at 36, at the lower surface of the rotor near one outer end thereof, and the other terminal end is exposed at 38, at the lower surface of the rotor at its axis. Terminal end 36 is positioned to make contact with the central conductor of any of the six other 3 connector elements 18, 24 22, 24, 26 and 28, and terminal end 38 is positioned to make contact with the central element 16 (see FIG. 2).

The inner bridging conductor'32 is provided with an upwardly projecting insulating contact operating pin'44 which is biased downwardly by a hairpin spring 46, whereby the operating pin pushes both end terminals of the conductor downwardly into good contact with the central conductors, and independently of the surrounding conductors.

The rotor 30 is mounted on an axially disposed shaft 48 "by means of ahairpin spring 50, which is fastened to the upper surface of the rotor by a'clamp 52 into which are threaded two bolts '54, and to cam 56, which is pinned to shaft 48 by pin 58, by clamp 66 and bolts 62. This mounting spring is of a form to transmit rotational movement of shaft 43 to the rotor, but also pushes the lower waveguide defining surfaces of the rotor into firm pressure contact with the upper plane surface of connector assembly plate 14 around the entire periphery of its bores independently of the central conductor, thereby assuring good electrical contact between these surfaces, to prevent cross-talk; It will be understood that other forms of universal mounting that achieve these ends may be substituted for spring 59, as hereinafter more fully set forth in the modified forms of switch structures shown in FEGS. 7 to 13 inclusive, so long as continuous contact is provided throughout the periphery of the outer tubular conductors surrounding the central conductors, and preferably by means independent thereof, as shown and described.

With the construction shown, the center of force of the'axial thrust exerted on the rotor 39 by the hairpin spring 50 is located substantially half-way between the switch axis represented by the central connector 38 and the outer terminal end 36 of the bridging connector 32. The two downwardly projecting cylindrical tubular inserts 64 and 66 circling the terminal ends 36 and 38 define the ends of the surrounding waveguide conductors. The inserts are fixedly secured in the rotor so. Since, as above noted, the focus of the-downward thrust of the hairpin spring 59 is-located approximately half-way between the two inserts, a firm engagement of the rotor with the connector plate 14 at all points of contact is assured, thus providing a sturdy and accurate support for the vertically shiftable inner bridging conductor 32. and likewise achieving a highly effective sealing of the gap between the connector'plate'M-and the RF channel contained in the rotor,

efining the surrounding waveguide.

Shaft 48 is rotatably mounted in bearings 63, and in the-embodiment shown is designed to be rotated by drive unit '71 but it may also be designed to be rotated manually, by means of a knob (not shown) on shaft 46. By rotation of the shaft the rotor may be positioned so as to provide a connection between the central-connector element 16 and any oneof the other elements 18, 2-6, 22, 24,26 and 28.

In order to reduce wear on terminal ends 36 and 38 of inner bridging conductor'SZ during rotation, the connector assembly plate 14 is provided with a detent ring '72 shown in section in FIGS. 1' and 6 having spaced depressions 74' adjacent to each outer connector element, and rotor body'3'9 is provided with an insulating lifter pin 76 hearing against conductor 32 at a location more or less central between its bends and riding'on operating ball '78. As best shown in F365. 1 and 6, ball 78 rides on a detent ring 62, and ball 78 and pin 76 are so dimensioned that when the rotor is between contacting positions- (FIG. 6) the inner bridging conductor 32 is lifted so that its terminal ends are clear of the surface of plate 14, but when the rotor isin a contacting position (FIG. 1) the ball rests in one ofthe depressions '74, permittingthe'bridging conductor to be pushed into contactby spring 46. The central conductor has sufficient freedom of movement in the insulatirig'blocks" 34 to permit this action.

In order to position the rotor in accurate regular contacting position at any one ,of the outer connecting elements, there is provided positioning mechanism, designated generally at 79 cooperating with cam 56, as shown in FIGS. 1, 4, 5 and 6. The positioning mechanism referred to acts to determine the angular position of shaft 48, and thus to determine the angular position of the rotor 3b. This positioning mechanism comprises two roller arms 80, each consisting of a hairpin-shaped strip carrying between its two legs a roller 82 rotatably mounted on a pin 84, and two springs 86 joining the roller arms at their'ends by means of pins 88 and 9b, and pressing the two arms towardeach other. This action is resisted by the bearing of rollers 82 against cam 56. By means of pins 88, which are located diagonally opposite each other, the roller arms are suspended from the cover plate 92 of switch housing 12, thereby preventin the positioning mechanism from rotating with cam 56.

0am 56, as best shown in FIG. 3, has twelve evenly spaced teeth with arcuate tooth spaces between them having a radius equal to the radius of rollers 82. As shown in FIGS. 3 and 4, normally the cam 56 is positioned so that the rollers lie in opposite tooth spaces. When shaft 43 is rotated, oppositely disposed cam teeth bear against the rollers forcing roller arms 86 to move in a direction away from the shaft, pivoting about pins 88. Springs 36 oppose this movement, and this opposing force, acting through the arms and rollers, always tends to rotate the cam into a position so that the roller may rest snugly in oppositely disposed tooth spaces resting against the rollers. The cam is so positioned on the shaft with respect to the rotor 35? that six of these positions, defined by alternate tooth spaces 92, correspond accurately to the six contacting positions of the rotor. The other six positions, defined by tooth spaces 94, correspond to out-ofcontact positions of the rotor. Thus it will be seen that accurate position of the rotor at all times is achieved by the positioning mechanism.

The operation of my improved switch will be described briefly as follows:

The rotor 36 is rigidly supported toturn as a unit with the control shaft 48 by the hairpin spring Stl, while at the same time over the area of contact with the stationary connector plate 14 as defined by the two circular inserts the rotor 30 is held firmly in engagement with the connectorplate 14. The center of gravity of the downward pressure exerted by the spring 50, being located about half-way between the innermost insert 63 and theoutermost insert 69, insures an even distribution of this downward pressure, which remains unchan ed during rotation of the switch from one to another position.

The universal connection provided by the hairpin spring 5!) has the advantage that it provides a connection between the rotor 39 and control shaft 48 which rigidly supports these parts against relative rotational movement while. permitting the rotor to adjust itself freely in any direction: to the surface of theconnector plate 14 under the yieldable ax-ial'thr'ust of the spring St The inner bridging conductor 32 isrnoved in an up and down direction against the centrally directed. thrust of hairpin spring 46 by the engagement of the ball 78 be-- tween the bridging conductor 32 and the cammed surface of the ring insert 7-2 in the connector plate 14. At thelocation of eaohswitch engaging position of the rotor 30, the ball 78 drops into a recess 74 in the insert 72 causing the two ends of the bridging conductor 32 to be moved quickly and firmly into engagement with the respective connectors 16 and 18. This arrangement of the switch make and break mechanism has been found of great advantage particularly as applied to a coaxial switch to insure a rapid simultaneous closing and opening of the switch contacts which avoids arcing, and which further reduces contact resistance and prevents electrical losses during switch operation.

Full enclosure of signal carrying elements, which include bridging connector 32 and contacts 36, 33, and 13, within rotor assembly 3t combined with freely seating spring enforced contact between the circular inserts and the base plate 114 prevents radiation of any of the radio frequency signals from said signal carrying elements to any signal conductive elements or connectors which are not in use in a given switch position. The high attenuation between used and unused positions and the low cross-talk achieved is one of the great points of merit in this type of switch design.

An alternative form of switch structure which embodies therein the several features of the invention is shown in FIGS. 7 to 10 inclusive of the drawings. The switch motor housing 19, switch housing 12 and base are identical with those shown in FIGS. 1 and 2. The base specifically comprises connector assembly plate 14 having one central connector element 16 and six connector elements 18, 2t), 22, 24, 26 and 28 arranged concentrically around it. The face of the assembly plate 14 is formed with spaced depressions 74 adjacent each outer connector element. As in the embodiment of FIGS. 1 to 6 inclusive the switch rotor is carried on a vertically disposed rotatable shaft -i8 which is driven by the electric motor 7t shown in FIG. 1. The rotor positioning mechanism is similar to that above described in connection with FIGS. 1, 4, 5 and 6.

The rotor in the modification shown in FIGS. 7 to 10 takes the form of a guide box 100 which is rigidly secured to the lower end of rotor shaft 48 for movement about the axis of shaft 48 above the connector assembly plate 14. The guide box 1% houses a bridging conductor assembly including a rotor body 102 which is mounted for universal movement within the guide box, and is spring biased yieldably against the connector assembly plate 14, so that the rotor 162 is held at all times squarely against the surface of the connector assembly plate 14. The rotor ltll. in turn houses inner bridging conductor 104 which is spring biased against the central conductors lo, 18 of the outer and central connector elements respectively.

The rotor body 102 is generally oblong in shape and is pressed downwardly by means of a bowed fiat spring 196 which is seated at its midportion against the cover portion of guide box 199 and at its two ends engages lugs 1%, 11d formed on the ends of the rotor ltli'. adjacent the lower edge thereof. This arrangement of spring ass and lugs 1598, Hit provides for complete freedom of adjustment of the rotor in every direction. The housing surface for the rotor comprises a boss 112. shaped to provide two end rings and a smaller central ring connected together, the boss 112 being formed on the bottom of the rotor 132 for engagement against the connector assembly plate 14.

The inner bridging conductor lild consists of a cylinrical casing 114 of non-conducting material which is bowed downwardly at each end and has mounted therein a conductor wire "116. A small leaf spring 113 seated against one face of a recess 1253 in the upper portion of the rotor body 1%; engages against an upwardly projecting lug 122 on the inner bridging conductor 104 to press the inner bridging conductor 1 34 yieldably against the central conductors 46, 42.

In order to avoid wear on the terminal ends of the wire 1&6 of the inner bridging conductor ltld during rotation, spaced depressions 7d are provided in the face of the connector assembly plate 14 adjacent each outor connector element, and the bridging conductor has formed thereon an insulated lifter pin 12 5 which rides on an operating ball 78 carried on the connector assembly plate 14. In each of the operating positions of the switch, as shown for example in FIG. 9, the ball 78 rests in a depression 7 so that the inner bridging conductor terminals are engaged with the central conductors 16, 18. During rotation of the rotor body N2 the ball '78 rides out or" the depression 74 causing the inner bridging conductor 194 to be lifted so that the terminal ends of wire 116 are clear of the surface of the plate 14.

The guide box rotor assembly described and illustrated in FIGS. 7 to 10 inclusive has the advantage that an extremely accurate positioning control is maintained over the rotor and associated bridging conductor while at the same time the parts are enabled to adapt themselves freely to the surf cc of the connector assembly plate 14 and thus to avoid leakage of the radio frequency signal from said signal carrying elements.

The rotor and bridging conductor assembly illustrated in FIGS. 7 to 10 inclusive has been found particularly suited for use in a switch adapted for the closing of selected peripheral outer connectors with one another. A switch of this general description is particularly shown in the modification of FIGS. 11 to 13 inclusive. The switch assembly illustrated in this latter modification comprises switch base connector assembly plate 14 which in this instance is provided only with the peripherally arranged connector elements '18, 20, 22, 24, 26 and 23, as shown in FIG. 2, and depressions 74 which are spaced between adjacent connectors to receive a bridging conductor lifting ball 78.

The switch rotor is mounted on rotatable shaft 43 which is driven by the motor '70 (see FIG. 1), and has secured thereto a rotor positioning mechanism including a cam 13!) formed with accurate tooth spaces similar to those described in connection with the switch structure shown in FIGS. 1 to 6 inclusive.

The rotor assembly of the switch shown in FIGS. 11 to 13 inclusive comprises two rotor bodies 1.32, 134 which are identical to that shown in FlGS. 7 to 10, including the rotor body and, housed therein, an inner bridging conductor iii-4 which is spring biased downwardly with relation to the rotor body by means of a leaf spring 113. The two rotor bodies 132., 134 are supported in parallel relation one at each side of the rotational axis of shaft is by means of a frame 136 comprising a square plate which is pressed downwardly by a coiled compression spring 1451 seated at one end in a bracket 142 secured to the lower end of shaft 48 and at its other end in a recess M4 in the plate 133. A pair of downwardly extending lugs mounted on the bracket 142 engage in recesses formed in the plate 138 and act as drivers, rotating the rotor assembly as a unit with shaft 48. A strap 146 rigidly secured by two screws 14 15% to one side of the plate 138 is provided at each end with hook shaped recesses which engage with lugs 1'52, 154 formed on the ends of rotor bodies 132, 134 respectively. A second strap 156 pivotally connected by a pin 15% to the other side of plate 138 has formed in the ends thereof recesses which engage lugs 160, 162 in the other ends of the rotor bodies 132, 134 respectively.

The arrangement of the rotor assembly above described is such as to permit a universal movement of each rotor body 132, i134 and to cause each said rotor body to be pressed downwardly so that it is held firmly and squarely in contact with the connector assembly plate at all times. In operation the entire assembly is pressed yieldably downward by spring 142. The plate 138 is free to tip sufficiently to insure a cross distribution of said downward pressure to both of said rotor bodies, and along the length of same, the rotor bodies are each freely rotatable about the axis of the supporting lugs formed on each end thereof, and a further adjustment is permitted by the rocking of the strap about its pivot 158.

The construction and operation of the bridging conductors housed in the respective rotor bodies is identical with that previously described in connection with the embodiment of FIGS. 7 to 10 inclusive, and need not be repeated.

Thus, it will be seen that the invention provides a novel coaxial or other waveguide switch structure having a unique universal mounting wherein continuous peripheral contact of the mating surrounding waveguide conductors is' established and maintained and wherein the central coaxial'conductors are maintained in suitable contact independently thereof yet releasably while switching. Various modifications of the preferred embodiments of the invention herein shown and described, yet within the spirit of the invention and the scope of the appended claims, will be apparent to those skilled in the radio frequency connector art.

The invention having been described, what is 1. A rotor assemby for a switch having a flat connec tor assembly plate with a plurality of tubular switch connectors terminating in flat end-on relation arranged thereon, and a rotatable rotor supporting means rotatably adjustable to any one of a plurality of connector bridging positions, which comprises a support ro'ta'tably guided for turning movement, a rotor body mounted for movement as a unit therewith, said support having means for biasing said rotor body against the connector assembly plate and provision for free adjustment of said rotor body about longitudinal and transverse axes, and a bridging conductor assembly including a tubular bridging conductor comprising a rigidly formed insulated element with separated contacts adapted for bridging selected switch connectors supported by said rotor body for universal movement relatively thereto for uniform contact of said connectors about the periphery thereof, and means biasing said bridging conductor against said plate.

2. A rotor assembly for a coaxial switch having a flat connector assembly plate with a plurality of switch connectors arranged thereon, and a rotatable rotor supporting and control shaft extending perpendicularly above said plate rotatably adjustable to any one of a plurality of connector bridging positions, which comprises a support in the form of an inverted boxlike structure attached to said rotor and having the open bottom side thereof overlying and in close proximity to said connector assembly plate, a rotor body which comprises an elongated casing loosely housed in said support, spring means within said boxlilie structure having a pivotal connection with each end of said rotor body for biasing said rotor body downwardly against said plate while permitting freedom of adjustment about longitudinal and transverse axes, and a bridging conductor assembly including an inner bridging conductor comprising a rigidly formed insulated element with separated contacts which is freely movable toward and away from said plate within said rotor body for bridging selected switch connectors, a leaf spring within said rotor biasing said inner bridging conductor against said plate, and cam and follower means between said connector assembly plate and said inner bridging conductor to raise said inner bridging conductor during rotation from one to another connector bridging position.

3. A coaxial switch having, in combination, a switch stator assembly comprising a flat connector assembly plate, connectors including a plurality of outer connectors circularly disposed about a central axis on said plate, a switch rotor assembly comprising a.- rotatable shaft mounted perpendicularly above said plate along said axis, a support rotatably guided from said shaft to turn therewith on said. axis, having pivotal connections with opposite ends of each of a pair of rotor bodies spaced from one another in parallel relation at opposite sides of said axis, spring means acting on said. support to bias said rotor bodies against said plate, a bridging conductor assembly associated with eachof said rotor bodies, each comprising an inner bridging conductor comprising a rigidly formed insulated element with separated contacts which is freely movable toward and away from said plate within said rotor body for bridging selected switch connectors, supported by said rotor body for movement relatively thereto against said connector assembly plate, and

claimed 8:? means biasing said inner bridging conductor against said connector assembly plate.

4-. A coaxial switch having in combination a switch stator assembly comprising a fiat connector assembly plate, connectors including a plurality of outer connectors circularly disposed about a centralaxis on said plate, a switch rotor assembly comprising a rotatable shaft mounted perpendicularly above said plate along said axis, a support rotatably guided from said shaft to turn therewith on said axis comprising a horizontally disposed.

member having parallel sides, a pair of rotor bodies, a strap rigidly secured to one of said sides having pivoted connections with the similarly directed ends with said rotor bodies, a second strap pivotally connected to the other of said parallel sides and having pivotal connections with the other of said rotor bodies, and a spring engaging a central portion of said member to bias said member and rotor bodies downwardly against said connector assembly plate, thus providing a uniform evenly directed pressure of said rotor bodies against said connector assembly plate, a bridging conductor assembly associated with each of said rotor bodies, each comprising an inner bridging conductor adapted for bridging selected switch connectors, supported by said rotor bodies for movement relatively thereto against said connector assembly plate, and means biasing said inner bridging conductor against said connector assembly plate.

5. A coaxial switch having, in combination, a switch housing, a switch stator assembly mounted in said housing comprising a central connector, and cooperating connectors circularly spaced about said central connector, 2. switch rotor mounted in said housing rotatable to a plurality of operating positions and comprising a bridging conductor assembly shiftable for connecting said central connector with any one of said cooperating connectors, a rotary control shaft supported perpendicularly to said switch stator assembly in said housing, means for rotating said shaft, and a hairpin spring connecting the switch rotor to said rotary control shaft providing a positive rotating connection therebetween and a spring pressed connection axially therebetween having a universal action to bias said switch rotor bodily against said switch stator assembly.

6. A coaxial switch having, in combination, a switch housing, a switch stator assembly mounted in said housing comprising a central connector, and cooperating connectors circularly spaced about said central connector, a switch rotor mounted in said housing rotatable to a plurality of operating positions and having a bridging conductor assembly movable with the rotor and including an inner bridging conductor axially movable thereon for connecting said central connector with any one of said cooperating connectors, a rotary control shaft supported perpendicularly to said switch stator assembly in said housing, means for rotating said shaft, a hairpin spring connecting the switch rotor to said rotary control shaft providing a positive rotating connection therebetween, and a spring pressed connection biasing said switch rotor bodily against said switch stator assembly, and a second hairpin spring connected between said shaft and said latter hairpin spring biasing said inner bridging conductor bodily against said connectors, and cam and follower connections between said inner bridging conductor and said switch stator operable to move said inner bridging conductor away from said connectors during rotational movement of said rotor from one, to another switch engaging position.

Referenees Cited in the file of this patent UNITED STATES PATENTS 

1. A ROTOR ASSEMBLY FOR A SWITCH HAVING A FLAT CONNECTOR ASSEMBLY PLATE WITH A PLURALITY OF TUBULAR SWITCH CONNECTORS TERMINATING IN FLAT END-ON RELATION ARRANGED THEREON, AND A ROTATABLE ROTOR SUPPORTING MEANS ROTATABLY ADJUSTABLE TO ANY ONE OF A PLURALITY OF CONNECTOR BRIDGING POSITIONS, WHICH COMPRISES A SUPPORT ROTATABLY GUIDED FOR TURNING MOVEMENT, A ROTOR BODY MOUNTED FOR MOVEMENT AS A UNIT THEREWITH, SAID SUPPORT HAVING MEANS FOR BIASING SAID ROTOR BODY AGAINST THE CONNECTOR ASSEMBLY PLATE AND PROVISION FOR FREE ADJUSTMENT OF SAID ROTOR BODY ABOUT LONGITUDINAL AND TRANSVERSE AXES, AND A BRIDGING CONDUCTOR ASSEMBLY INCLUDING A TUBULAR BRIDGING CONDUCTOR COMPRISING A RIGIDLY FORMED INSULATED ELEMENT WITH SEPARATED CONTACTS ADAPTED FOR BRIDGING SELECTED SWITCH CONNECTORS SUPPORTED BY SAID ROTOR BODY FOR UNIVERSAL MOVEMENT RELATIVELY THERETO FOR UNIFORM CONTACT OF SAID CONNECTORS ABOUT THE PERIPHERY THEREOF, AND MEANS BIASING SAID BRIDGING CONDUCTOR AGAINST SAID PLATE. 